The present invention relates generally to an integrated circuit package and other such electronic devices fabricated using the technique of wire bonding together certain components making up the device, and more specifically to a method of and arrangement for preventing the bonding wires from contacting, at points other than their endpoints, certain other components of the integrated circuit package or other such devices.
A typical integrated circuit package includes a die having an array of die input/output bond pads and a leadframe having an array of electrically conductive leads respectively connected to corresponding die bond pads by means of cooperating bonding wires. An example of such a package is illustrated in FIG. 1 and generally designated by the reference numeral 10. Integrated circuit package 10 is shown including a leadframe 12 having an array of electrically conductive leads, one of which is indicated at 14. Leadframe 12 supports a die 16 having an array of die input/output bond pads, one of which is indicated at 18. The electrically conductive lead 14 is shown connected with die bond pad 18 by means of an electrically conductive bonding wire 20.
In the particular example illustrated in FIG. 1, it is conventional practice to use a thermosonic or thermocompression ball bonding tool to first ball bond the free end of wire 20 to pad 18, as indicated by ball bond 22, and thereafter stitch bond the opposite end of bonding wire 20 to lead 14, as indicated by stitch bond 24. In certain instances, there are good reasons to reverse this process, as is illustrated in FIG. 2. Referring to FIG. 2, in reverse bonding, a ball bonding tool is used to first ball bond the free end of wire 20 to lead 14 on leadframe 12, as indicated by ball bond 22, and thereafter stitch bond the opposite end of wire 20 to die bond pad 18 on die 16, as indicated by stitch bond 24. However, applicants have discovered a potential problem when reverse bonding. After stitch bonding wire 20 to die bond pad 18 as indicated by stitch bond 24, bonding wire 20 may come into contact with the edge of die 16 as indicated by contact point 26 causing a die edge short.
FIG. 6 illustrates parts of the integrated circuit package including leadframe 12, die 16 and an array of bonding wires as described above supported by a heater block 36. It is conventional practice to use this type of heater block, which is a component of the equipment that may be used in manufacturing the package, to support the components during the wire bonding process. However when reverse bonding, as described above, this configuration has the potential problem of the above mentioned die edge short. The present invention eliminates this problem in a reliable and uncomplicated way.